1. Field of the Invention
The present invention relates to a technology of wirelessly transmitting data to a reception terminal having a reception available state and a reception unavailable state, and being configured to extend a current reception available period in the case of receiving data in the reception available state.
Priority is claimed on Japanese Patent Application No. 2012-090488, filed Apr. 11, 2012, the content of which is incorporated herein by reference.
2. Description of the Related Art
Bluetooth (trademark) is the standard for short-range wireless communication in a wireless network (hereinafter, a “piconet”) including one controlling terminal (hereinafter, “master”) and one or more controlled terminals (hereinafter, “slaves”) or wireless communication between devices requiring low power consumption. Regarding the short-range wireless communication, data are transmitted between the master and the slaves under control of the master.
Additionally, the Bluetooth (trademark) is the standard for wireless communication based on various definitions disclosed in, for example, “SPECIFICATION OF THE BLUETOOTH SYSTEM (ver. 4.0)” (hereinafter, “Non-Patent Document 1”). A communication method using the Bluetooth (trademark) is defined by various documents disclosed on Bluetooth SIG (https:/www.bluetoofh.org/apps/content/).
Regarding the Bluetooth (trademark), a low power consumption mode called a “sniff mode”, which is slave specific, is defined. In the sniff mode, as shown in FIG. 1, each reception interval (hereinafter, “sniff interval”) includes a reception available period (hereinafter, “sniff slot”) and a reception unavailable period. The sniff slot commences from a transmission period start point (hereinafter, “anchor point”). In the sniff slot, data can be transmitted. The reception unavailable period commences from the end of the sniff slot. In the reception unavailable period, data cannot be transmitted, and a process relating to transmission and reception is not performed, thereby reducing the power consumption.
The sniff mode is further defined as follows. As shown in FIG. 2, in a case where the slave receives data from the master in a predetermined initial period (hereinafter, a “sniff attempt”) included in the sniff slot, the slave extends the sniff slot by a predetermined extension duration (hereinafter, a “sniff timeout”) from the time when the slave receives the data. Thus, even in a case where fragmented data (segmented data) are transmitted from tire master, the slave does not enter the transmission unavailable state until transmission of all the fragmented packets is complete,